Long span wings are desirable for commercial aircraft as they are more aerodynamically efficient than shorter wings. The greater aerodynamic efficiency results in lower fuel consumption and, therefore, lower operating costs.
However, existing airport designs place limits on aircraft wingspan. Airport designs are based on International Civil Aviation Organization (ICAO) Codes A through F, which establish dimensional limits on wingspan, landing gear width, length, etc. For instance, an ICAO Code E airport limits wingspan to less than 65 meters so that aircraft can fit within runways, taxiways and gate areas.
A folding wing design may be used to reduce the span of these wings to fit within the limitations of an existing airport's infrastructure. Folding wings may be folded to fit within parking areas and taxiways, and they may be deployed prior to takeoff to increase wing span.
Folding wing designs are commonly used in naval aircraft. Folding wings enable naval aircraft to occupy less space in confined aircraft carrier hangars. Wing fold joints in naval aircraft use highly loaded hinges and locking pins acting over very small wing bending reaction moment arms. However, naval aircraft are much smaller than large commercial aircraft, and present folding wing designs for naval aircraft are optimized to different mission parameters than large commercial aircraft.
In commercial aircraft, a folding wing design may be scaled up. High reaction loads may be overcome by increasing the size of the hinges and locking pins. However, these size increases would increase aircraft weight, and increases in aircraft weight are undesirable because operating costs such as fuel costs are increased. Consequently, the increase in weight negates the advantages offered by the long span wings.